Chemistry of Asphaltenes

A survey of the methods used to determine asphaltene "structure" indicates that there are serious shortcomings in all of the methods because of the assumptions required to derive the molecular formulae. The continued insistence that a complex fraction such as asphaltenes, derived in a one-step process from petroleum as a consequence of its insolubility in nonpolar solvents, has a definitive molecular structure is of questionable value to petroleum technology, and it is certainly beyond the scope of the available methods to derive such formulae. Asphaltenes would best be described in terms of several structural types rather than definite molecular structures.